Surface enhanced raman spectroscopy (SERS) substrates exhibiting uniform high enhancement and stability

Abstract

An improved substrate for Raman spectroscopy of an analyte comprises a porous metal film. Enhancement factors and uniformity of the substrate can be enhanced by electrochemical roughening of the film. Improved sensors and spectrometers using such substrates are also described.

Description

REFERENCE TO RELATED APPLICATION [0001] This application claims priority of U.S. Provisional Patent Application Ser. No. 60 / 612,291, filed Sep. 22, 2004, the entire content of which is incorporated herein by reference.GOVERNMENT SUPPORT [0002] This material is based upon work support by the United States Navy Office of Naval Research under Award No. N00014-03-1-0226.FIELD OF THE INVENTION [0003] The invention relates to substrates, in particular to porous metal substrates, useful for analytical techniques such as surface enhanced Raman spectroscopy (SERS). BACKGROUND OF THE INVENTION [0004] In 1974, it was discovered that the Raman scattering signal of certain compounds could be enhanced by orders of magnitude proximate to metallic surfaces roughened on the scale of tens to hundreds of nanometers, a technique called Surface Enhanced Raman Spectroscopy (SERS). [0005] When laser light scatters from a metal surface, typically one photon in a million interacts with the vibrational state...

AI Technical Summary

Benefits of technology

[0013] Methods according to embodiments of the present invention allow preparation of substrates showing high values of SERS enhancement factors, that are robust, can be cleaned and reused, and which show a high degree of uniformity.

[0016] In further embodiments of the present invention, a method for enhanced detection of an analyte comprises preparing a textured metal film, for example a porous metal film, lithographed patterned film, or other deposited film, and then further roughening the textured metal film to provide a substrate for the analyte. The further roughening can give greater values of enhancement factors for SERS of the analyte on the substrate. In representative examples, the textured metal film is a porous metal film, and electrochemical roughening the porous metal film gives improved substrates for SERS.

Problems solved by technology

However, laboratory substrate preparations are poor in terms of reproducibility, and typically the enhancement factors vary by orders of magnitude from point-to-point across a given substrate.

At present, SERS systems have seen little use in practical, field-portable chemical sensor systems, primarily due to poor reproducibility of SERS-active substrates.

However, conventional substrate preparation methods preparations are notoriously irreproducible.

However, there is no suggestion in these patents to use metallic structures in any analytical technique.

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